//  一.将下面异步代码使用Promise的方式改进
setTimeout(function() {
    var a = 'hello'
    setTimeout(function() {
        var b = 'lagou'
        setTimeout(function() {
            var c = 'I ♥ U'
            console.log(a + b + c)
        }, 10)
    }, 10)
}, 10)





// 答案
//定义统一方法
function fn(msg) {
    var promise = new Promise((resolved, rejected) => {
        setTimeout(() => {
            resolved(msg)
        }, 10)
    });
    return promise;
}

fn().then(function() {
    return fn("hello")
}).then(value => {
    return fn(value + "lagou")
}).then(value => {
    return fn(value + "I ♥ U")
}).then(value => {
    console.log(value)
})